In this study, we investigated a method for accurately measuring myocardial T(1) for the quantification of myocardial blood flow (MBF) with arterial spin labeling (ASL). A single-shot gradient-echo (GE)-based ASL sequence with an adiabatic hyperbolic secant inversion recovery pulse was modified to acquire a pair of myocardial T(1)'s within a breath-hold. A multivariable regression algorithm that accounted for the magnetization saturation effects was developed to calculate T(1). The MBF was then determined with a well-developed model. The accuracy of our T(1) calculation was first evaluated in a phantom, and then in six dogs for the MBF calculation, with (N = 4) and without (N = 2) coronary artery stenosis. In the phantom study, the accuracy of T(1) measured with a slice-selective inversion prepared pulse was within 2.5% of error. In healthy dogs, the MBF increased 2-5 times during vasodilation. In contrast, regional differences of MBF were well visualized in the stenotic dogs during vasodilation (perfusion reserve of 2.75 +/- 0.83 in normal myocardium, and 1.46 +/- 0.75 in the stenotic area). A correlation analysis revealed a close agreement in MBF between the ASL and microsphere (MS) in both healthy and stenotic dogs. In summary, the modified ASL technique and T(1) regression algorithm proposed here provide an accurate measurement of myocardial T(1) and demonstrate potential for reliably assessing MBF at steady state.

Purpose The approved dose of ipilimumab is 3 mg/kg infused over 90 minutes; however, in clinical trials, 10 mg/kg has also been infused over 90 minutes. At this higher dose, patients receive 3 mg/kg within the first 27 minutes of treatment. We sought to determine whether the standard dose of 3 mg/kg could be safely infused over 30 minutes. Methods We reviewed retrospectively the incidence of infusion-related reactions (IRRs) to ipilimumab at our institution in patients receiving doses of either 3 or 10 mg/kg infused over 90 minutes. Our findings led to a change in institutional guidelines for ipilimumab infusion time from 90 minutes to 30 minutes. We reviewed the first 14 months of our prospective experience using a 30-minute infusion of ipilimumab. Results Between April 1, 2008, and June 30, 2013, 595 patients received 2,507 doses of ipilimumab infused at either 3 mg/kg (n = 457) or 10 mg/kg (n = 138) over 90 minutes. Although the 10 mg/kg group had a higher incidence of IRRs (4.3%) than the 3 mg/kg group (2.2%), this difference was not statistically significant (P = .22). In 120 patients treated prospectively with ipilimumab 3 mg/kg infused over 30 minutes, seven patients (5.8%) had an IRR (P = .06 compared with 90-minute infusions). All IRRs occurred at dose 2; six were grade 2, and one was grade 3. All seven patients received subsequent doses of ipilimumab safely, the majority with premedication. Conclusion Ipilimumab at 3 mg/kg can be infused safely over 30 minutes with an acceptably low incidence of IRRs. After an IRR, patients can safely receive additional doses of ipilimumab with premedication.

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